Rotary drill bit



Au 10, 19.26. V H. H. HULSEN ET AL ROTARY DRILL BIT Filed Dec. 21. 1923 6 4W0; L I flaw div/ i v i M A atented-Aug. 10, 1926.

. 'i NI' D- ST Emmy H. HULSEN arm SHELLE sienorts or ONEJIALF TO no ATE-s Y e. woonmlrr, or LOS worms, camrormm, As ma DISC err conrm, or LOS enemas, GALI- roman, a. CORPORATION or carrrdnmn.

- BOTABYQDIRILL, BIT.

Application filed December Our presentinvention' being referred to as a rotary drill bit, it may be understood to Joean object of this invention to provide a drill bit of novel type suitable for use in drilling of deep wells, such as oil wells.

It is anobject of this invention to provide a rotary drill bit of especially rugged and effective construction, comprising a pair of removable blades; and. in a preferred embodiment of our invention, each of the blades referred to may be curved in two planes and provided with means for secure ing the same to one of two opposite, inner faces of a slot extending through a head provided with means for the secure retention of said blades in their intended relationship, althoughso constructed as to permit of the readyremoval thereof, forcpurposes of repair or replacement. 9 It is a further object of our invention to f provide a rotary drill bit in the form of a main body comprising a shank threaded -at its upper end and provided'with a longitudinal circulation channelextehding to a slot by whichthe head of said-body may be divided into two-eubst limbs; and, in a preferred embodiment of our invention the said slot may be provided with upward extensions constituting recesses for the secure retention of the mentiened blades, which may be regarded as countersunk-therein in such manner as to provide shoulders engaging the inner, ver' tical lateral edges of sai'd'blades. It is a further object of our invention to rovide a rotary drill bit comprising reovable blades; whose inner and upper cor ners may be substantially rectangular but whose outer corners may be respectively in; clined downward in a manner favorable to the efficiency and tQ-thewithdrawal thereof, both the bottom edges and the outer edges of the respective blades being preferably forwardly curved, and preferably formed of a toolor other special steel, each blade being preferably pierced or otherwise provided with a transverse aperture and optionally also with a squaredm similar. countersin'k, adapted to receive the head of a bolt. The threaded end of this may be engaged by a nut, for which a corresponding recess may .be provided in the edge of a air of limbs into which the body of a drill it may be divided by a transverse slot, the

antiallyidenticak 21 1923f Serial. 3N0. 681,945."

, construction of all parts being preferably such-as to force the cuttings produced by the rotation, of our novel bit inwardly and upwardly and out through the top of the mentioned slot, which may be bevelled in adaptation to the movement referred to.- '60" Other obiects of our invention will ap pear from'the following description of "a preferredembodiment thereof, alternative types of blades beingsuggested, and from the appended claims, taken-in connection with accompanying drawings, in which Fig. 1 may be regarded as a side elevation of a drill bit of our improved design,

Fig; 2 being then regarded 'as a front elevation of the same, and,

Fig. 3 being a vertical section, on line .3"'3- of Fig. 1.

Fig. 4 is a bottom plan view, having an obvious relationship to the side elevation shown in Fig. 1. v

Figs. 5 and. 6 are respectively front and" edge elevations of an alternative type of blade hereinafter referred to.

Figs. 7 and 8 are respectively side and edge views of an additional alternative'type' of blade. p f Y Fig. 9 is a horizontal section corresponding" to the line 9'9 of Fig. 1 but suggesting the employment of blades unequal in breadth, as hereinafter referred to. 85

In that specific embodiment of ur inventiondgustrated in Figs. 1, 2, 3 and 4, it will be un erstood that, the main body B of our drill bit comprises head 1 provided with a transverse slot 2 extending in a verti' al plane and through thejoenter of said head, this head being preferably integral with a.

shank 3, shown as provided atitsupper end with aprojection 4 carrying ausual'tool thread and as provided with a longitudinal central circulation channel 5, through which water or slush may be forced.

vIt being obvious that the slot 2, or its eiuivalent, divides the head 1 into a pair 0 symmetrically disposed limbs 1 and 1 we consider it advanta eons to secure to the substantially parallel inner faces of these i limbs a pair 0 novel removable-bladesfi, 6',

- which ma be given any desired specific configuration but which are preferably provided with substantiall fiat bodies of sub'-. stan'tially uniform thic ess, and with outwardly and forwardly curved cutting edges.

theform. of our invention shown in Figs. 1, 2, 3, and 4., each of the mentioned blades may compnse a body roughly rectangular in out-line, only the inner and .upper corner thereof being, however, shown and preserved as a true right angle. It being understood that t e lower and outer edges, these being the rorwardly curved edges of our novel blades, may advantagev ously be formed of a tool or other special steel, "and that a downwardly projecting point may advantageously be provided either at the outer lower corner 7 of each blade or at an-intermediate point (as suggested in' Figs. and 7}, we consider it advantageous to retain the respective blades not only by threaded 'means such as the bolts 8, shown as extending transversely through v the said blades'and through the corresponding limbs l and 1 but also by providing asuitable countersink or depression 9 in each of said limbs, the depth of each depression preferably corresponding to the thickness of the body of the blade to be retained therein, and its outline being such that a blade may closely interfit therewith, the [depressions shown in Figs. 1, 3 and 9 being such as to constitute practically upward lateral extensions of the slot 2, lateral shoulders 10 be ing, "however, provided to constitute stops or abutments engaged by the inner and substantially vertical edges of the respective blades. The depressions 9 constitute sockets extending upwardly at the side of the slot.

and the upper ends of the blades 6 slide up into these sockets so as to assist in firmly holding the blade;

Each blade may not only be cast or tapped for a bolt 8but also provided with a recthe nuts 14 upon the outer or threaded ends of bolts 8.

It should be understood that we may either form the entire blades 6 from a suitable special steel, or we may alternatively form the bodies thereof of a suitable mild or other steel, upon which cutting'edges of a preferred harder composition may be welded and renewed from time to time; and we may either employ two substantially identical blades, as indicated in Figs. 1, 2, 3 and 4, or wemay employ blades differing in configuration and width, one usual incidental result of the latter construction being atendency. for our bit to walk within a hole.

Depending upon the depth atwhich' we may be working, and character of rock encountered, we may,alternatively employ either bits with blades having cutting points at the outer lower corners thereof, as shown in Figs. 1, 2 and 3, or bits provided with blades of any suitable alternative design, two alternative configurations being best illustrated respectively in Figs. 5 and/Z.

It will be obvious that in the employment of our novel drill bit, slush being forced downward through the channel 5 or its equivalent and both the lower edge 13 and the lateral edge 14 of a blade 6 or its equivalent being eifective, by reason of the men tioned. curvature in the cutting edges thereof, to force loosened material upward and inward within the slot 2; and b-evelling of the upper transverse terminal faces 15 of,

the mentioned slot may be advantageous in feeding cuttings upward and outward to deliver the same from a well hole. It will be noted that the bevelled terminal faces 15 are on each side of a central projection from the head, extending into the slot as shown in Fig. 3 and that the blades engage at their upper edgesbetween the upper part of the limbs and the central projection, therefore forming. a rigid locking support for the Q blades. This detail is brought out in Fig. 1, the tops of the blades being indicated by the dotted line in Fig. 3. l i Although we have herein described one complete embodiment of our invention, suggesting various specific alternatives in detail, it should be understood that numerous different modifications might be made without involving a departure from the spirit and scope of our invention and also that various features thereof might be independently employed, the actual scope of our .invention being, however, indicated by the following claims: What we claim is: r

1. A drill bit having in combination a main body with a head provided with a transverse slot forming a pair of depending limbs on each side of the slot, a central projection extending downwardly slightly into the slot, a pair of removable cutter blades immovably attached to thelimbs of the head with their upper edges engaging the limbs and the downward projection of the head, the blades being secured in a recess in the limbs and having a bearing against a square shoulder formed by the recess.

2. A drill bit comprising in combination a main body having a head at its lower end provided with a transverse slot forming a pair of depending limbs, the faces of the limbs being in substantially parallel planes spaced substantially an equal distance from .1

blades'secured immovably to the inside faces of the limbs with their upper edges engaging the upper portion of the limbs and the central projection, the blades being secured in a recess in the limbs, said recess having a vertical shoulder adapted to'engage the.

back of the blades and-the said limbs having counter-sinks in their outer faces with bolts secured in the counter-sinks clamping the blades.

3T"II1" a drill bit, a main body having a threaded shankand ahead that is divided by a substantially vertical slot forming separate limbs having substantially parallel inner faces, said. head being provided with a pair of,oppositely extending removable cutter blades oppositely projecting from the said inner faces of said limbs and retained therein by intertitt'ing Within recess-es terminating laterally in substantially vertical shoulders 4. In a drill bit, a main body having a threaded shank and a head that is divided b. a substantiall vertical slot formin y b cutter blades oppositely projecting from the said inner faces of said limbs, said blades being substantially right-angled at upper and inner corners thereof and said head being recessed to interfit with said'right-angled corner and to provide a vertically extending shoulder constituting an abutment therefor. W

5. In a drill bit, a main body' having a threaded shank and a head that is divided by a, substantially vertical slot forming separate limbs having substantially parallel inner faces, said head being provided with a pair of oppositely extending removable cutter blades oppositely projecting from the said inner faces of said limbs, said blades having cutting edges'at unequal distance HENRY H. HULSEN. SHELLEY G; WOODRUFF. 

